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-rw-r--r--contrib/llvm/tools/clang/lib/CodeGen/CGCXX.cpp471
1 files changed, 471 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGCXX.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGCXX.cpp
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+++ b/contrib/llvm/tools/clang/lib/CodeGen/CGCXX.cpp
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+//===--- CGDecl.cpp - Emit LLVM Code for declarations ---------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code dealing with C++ code generation.
+//
+//===----------------------------------------------------------------------===//
+
+// We might split this into multiple files if it gets too unwieldy
+
+#include "CGCXXABI.h"
+#include "CodeGenFunction.h"
+#include "CodeGenModule.h"
+#include "Mangle.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/Frontend/CodeGenOptions.h"
+#include "llvm/ADT/StringExtras.h"
+using namespace clang;
+using namespace CodeGen;
+
+/// Determines whether the given function has a trivial body that does
+/// not require any specific codegen.
+static bool HasTrivialBody(const FunctionDecl *FD) {
+ Stmt *S = FD->getBody();
+ if (!S)
+ return true;
+ if (isa<CompoundStmt>(S) && cast<CompoundStmt>(S)->body_empty())
+ return true;
+ return false;
+}
+
+/// Try to emit a base destructor as an alias to its primary
+/// base-class destructor.
+bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
+ if (!getCodeGenOpts().CXXCtorDtorAliases)
+ return true;
+
+ // If the destructor doesn't have a trivial body, we have to emit it
+ // separately.
+ if (!HasTrivialBody(D))
+ return true;
+
+ const CXXRecordDecl *Class = D->getParent();
+
+ // If we need to manipulate a VTT parameter, give up.
+ if (Class->getNumVBases()) {
+ // Extra Credit: passing extra parameters is perfectly safe
+ // in many calling conventions, so only bail out if the ctor's
+ // calling convention is nonstandard.
+ return true;
+ }
+
+ // If any fields have a non-trivial destructor, we have to emit it
+ // separately.
+ for (CXXRecordDecl::field_iterator I = Class->field_begin(),
+ E = Class->field_end(); I != E; ++I)
+ if (const RecordType *RT = (*I)->getType()->getAs<RecordType>())
+ if (!cast<CXXRecordDecl>(RT->getDecl())->hasTrivialDestructor())
+ return true;
+
+ // Try to find a unique base class with a non-trivial destructor.
+ const CXXRecordDecl *UniqueBase = 0;
+ for (CXXRecordDecl::base_class_const_iterator I = Class->bases_begin(),
+ E = Class->bases_end(); I != E; ++I) {
+
+ // We're in the base destructor, so skip virtual bases.
+ if (I->isVirtual()) continue;
+
+ // Skip base classes with trivial destructors.
+ const CXXRecordDecl *Base
+ = cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+ if (Base->hasTrivialDestructor()) continue;
+
+ // If we've already found a base class with a non-trivial
+ // destructor, give up.
+ if (UniqueBase) return true;
+ UniqueBase = Base;
+ }
+
+ // If we didn't find any bases with a non-trivial destructor, then
+ // the base destructor is actually effectively trivial, which can
+ // happen if it was needlessly user-defined or if there are virtual
+ // bases with non-trivial destructors.
+ if (!UniqueBase)
+ return true;
+
+ /// If we don't have a definition for the destructor yet, don't
+ /// emit. We can't emit aliases to declarations; that's just not
+ /// how aliases work.
+ const CXXDestructorDecl *BaseD = UniqueBase->getDestructor();
+ if (!BaseD->isImplicit() && !BaseD->hasBody())
+ return true;
+
+ // If the base is at a non-zero offset, give up.
+ const ASTRecordLayout &ClassLayout = Context.getASTRecordLayout(Class);
+ if (ClassLayout.getBaseClassOffset(UniqueBase) != 0)
+ return true;
+
+ return TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Base),
+ GlobalDecl(BaseD, Dtor_Base));
+}
+
+/// Try to emit a definition as a global alias for another definition.
+bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
+ GlobalDecl TargetDecl) {
+ if (!getCodeGenOpts().CXXCtorDtorAliases)
+ return true;
+
+ // The alias will use the linkage of the referrent. If we can't
+ // support aliases with that linkage, fail.
+ llvm::GlobalValue::LinkageTypes Linkage
+ = getFunctionLinkage(cast<FunctionDecl>(AliasDecl.getDecl()));
+
+ switch (Linkage) {
+ // We can definitely emit aliases to definitions with external linkage.
+ case llvm::GlobalValue::ExternalLinkage:
+ case llvm::GlobalValue::ExternalWeakLinkage:
+ break;
+
+ // Same with local linkage.
+ case llvm::GlobalValue::InternalLinkage:
+ case llvm::GlobalValue::PrivateLinkage:
+ case llvm::GlobalValue::LinkerPrivateLinkage:
+ break;
+
+ // We should try to support linkonce linkages.
+ case llvm::GlobalValue::LinkOnceAnyLinkage:
+ case llvm::GlobalValue::LinkOnceODRLinkage:
+ return true;
+
+ // Other linkages will probably never be supported.
+ default:
+ return true;
+ }
+
+ llvm::GlobalValue::LinkageTypes TargetLinkage
+ = getFunctionLinkage(cast<FunctionDecl>(TargetDecl.getDecl()));
+
+ if (llvm::GlobalValue::isWeakForLinker(TargetLinkage))
+ return true;
+
+ // Derive the type for the alias.
+ const llvm::PointerType *AliasType
+ = getTypes().GetFunctionType(AliasDecl)->getPointerTo();
+
+ // Find the referrent. Some aliases might require a bitcast, in
+ // which case the caller is responsible for ensuring the soundness
+ // of these semantics.
+ llvm::GlobalValue *Ref = cast<llvm::GlobalValue>(GetAddrOfGlobal(TargetDecl));
+ llvm::Constant *Aliasee = Ref;
+ if (Ref->getType() != AliasType)
+ Aliasee = llvm::ConstantExpr::getBitCast(Ref, AliasType);
+
+ // Create the alias with no name.
+ llvm::GlobalAlias *Alias =
+ new llvm::GlobalAlias(AliasType, Linkage, "", Aliasee, &getModule());
+
+ // Switch any previous uses to the alias.
+ llvm::StringRef MangledName = getMangledName(AliasDecl);
+ llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
+ if (Entry) {
+ assert(Entry->isDeclaration() && "definition already exists for alias");
+ assert(Entry->getType() == AliasType &&
+ "declaration exists with different type");
+ Alias->takeName(Entry);
+ Entry->replaceAllUsesWith(Alias);
+ Entry->eraseFromParent();
+ } else {
+ Alias->setName(MangledName);
+ }
+
+ // Finally, set up the alias with its proper name and attributes.
+ SetCommonAttributes(AliasDecl.getDecl(), Alias);
+
+ return false;
+}
+
+void CodeGenModule::EmitCXXConstructors(const CXXConstructorDecl *D) {
+ // The constructor used for constructing this as a complete class;
+ // constucts the virtual bases, then calls the base constructor.
+ EmitGlobal(GlobalDecl(D, Ctor_Complete));
+
+ // The constructor used for constructing this as a base class;
+ // ignores virtual bases.
+ EmitGlobal(GlobalDecl(D, Ctor_Base));
+}
+
+void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
+ CXXCtorType Type) {
+ // The complete constructor is equivalent to the base constructor
+ // for classes with no virtual bases. Try to emit it as an alias.
+ if (Type == Ctor_Complete &&
+ !D->getParent()->getNumVBases() &&
+ !TryEmitDefinitionAsAlias(GlobalDecl(D, Ctor_Complete),
+ GlobalDecl(D, Ctor_Base)))
+ return;
+
+ llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXConstructor(D, Type));
+ setFunctionLinkage(D, Fn);
+
+ CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
+
+ SetFunctionDefinitionAttributes(D, Fn);
+ SetLLVMFunctionAttributesForDefinition(D, Fn);
+}
+
+llvm::GlobalValue *
+CodeGenModule::GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
+ CXXCtorType Type) {
+ GlobalDecl GD(D, Type);
+
+ llvm::StringRef Name = getMangledName(GD);
+ if (llvm::GlobalValue *V = GetGlobalValue(Name))
+ return V;
+
+ const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
+ const llvm::FunctionType *FTy =
+ getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type),
+ FPT->isVariadic());
+ return cast<llvm::Function>(GetOrCreateLLVMFunction(Name, FTy, GD));
+}
+
+void CodeGenModule::EmitCXXDestructors(const CXXDestructorDecl *D) {
+ // The destructor in a virtual table is always a 'deleting'
+ // destructor, which calls the complete destructor and then uses the
+ // appropriate operator delete.
+ if (D->isVirtual())
+ EmitGlobal(GlobalDecl(D, Dtor_Deleting));
+
+ // The destructor used for destructing this as a most-derived class;
+ // call the base destructor and then destructs any virtual bases.
+ EmitGlobal(GlobalDecl(D, Dtor_Complete));
+
+ // The destructor used for destructing this as a base class; ignores
+ // virtual bases.
+ EmitGlobal(GlobalDecl(D, Dtor_Base));
+}
+
+void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
+ CXXDtorType Type) {
+ // The complete destructor is equivalent to the base destructor for
+ // classes with no virtual bases, so try to emit it as an alias.
+ if (Type == Dtor_Complete &&
+ !D->getParent()->getNumVBases() &&
+ !TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Complete),
+ GlobalDecl(D, Dtor_Base)))
+ return;
+
+ // The base destructor is equivalent to the base destructor of its
+ // base class if there is exactly one non-virtual base class with a
+ // non-trivial destructor, there are no fields with a non-trivial
+ // destructor, and the body of the destructor is trivial.
+ if (Type == Dtor_Base && !TryEmitBaseDestructorAsAlias(D))
+ return;
+
+ llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXDestructor(D, Type));
+ setFunctionLinkage(D, Fn);
+
+ CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
+
+ SetFunctionDefinitionAttributes(D, Fn);
+ SetLLVMFunctionAttributesForDefinition(D, Fn);
+}
+
+llvm::GlobalValue *
+CodeGenModule::GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
+ CXXDtorType Type) {
+ GlobalDecl GD(D, Type);
+
+ llvm::StringRef Name = getMangledName(GD);
+ if (llvm::GlobalValue *V = GetGlobalValue(Name))
+ return V;
+
+ const llvm::FunctionType *FTy =
+ getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), false);
+
+ return cast<llvm::Function>(GetOrCreateLLVMFunction(Name, FTy, GD));
+}
+
+static llvm::Value *BuildVirtualCall(CodeGenFunction &CGF, uint64_t VTableIndex,
+ llvm::Value *This, const llvm::Type *Ty) {
+ Ty = Ty->getPointerTo()->getPointerTo()->getPointerTo();
+
+ llvm::Value *VTable = CGF.Builder.CreateBitCast(This, Ty);
+ VTable = CGF.Builder.CreateLoad(VTable);
+
+ llvm::Value *VFuncPtr =
+ CGF.Builder.CreateConstInBoundsGEP1_64(VTable, VTableIndex, "vfn");
+ return CGF.Builder.CreateLoad(VFuncPtr);
+}
+
+llvm::Value *
+CodeGenFunction::BuildVirtualCall(const CXXMethodDecl *MD, llvm::Value *This,
+ const llvm::Type *Ty) {
+ MD = MD->getCanonicalDecl();
+ uint64_t VTableIndex = CGM.getVTables().getMethodVTableIndex(MD);
+
+ return ::BuildVirtualCall(*this, VTableIndex, This, Ty);
+}
+
+llvm::Value *
+CodeGenFunction::BuildVirtualCall(const CXXDestructorDecl *DD, CXXDtorType Type,
+ llvm::Value *&This, const llvm::Type *Ty) {
+ DD = cast<CXXDestructorDecl>(DD->getCanonicalDecl());
+ uint64_t VTableIndex =
+ CGM.getVTables().getMethodVTableIndex(GlobalDecl(DD, Type));
+
+ return ::BuildVirtualCall(*this, VTableIndex, This, Ty);
+}
+
+/// Implementation for CGCXXABI. Possibly this should be moved into
+/// the incomplete ABI implementations?
+
+CGCXXABI::~CGCXXABI() {}
+
+static void ErrorUnsupportedABI(CodeGenFunction &CGF,
+ llvm::StringRef S) {
+ Diagnostic &Diags = CGF.CGM.getDiags();
+ unsigned DiagID = Diags.getCustomDiagID(Diagnostic::Error,
+ "cannot yet compile %1 in this ABI");
+ Diags.Report(CGF.getContext().getFullLoc(CGF.CurCodeDecl->getLocation()),
+ DiagID)
+ << S;
+}
+
+static llvm::Constant *GetBogusMemberPointer(CodeGenModule &CGM,
+ QualType T) {
+ return llvm::Constant::getNullValue(CGM.getTypes().ConvertType(T));
+}
+
+const llvm::Type *
+CGCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) {
+ return CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());
+}
+
+llvm::Value *CGCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
+ llvm::Value *&This,
+ llvm::Value *MemPtr,
+ const MemberPointerType *MPT) {
+ ErrorUnsupportedABI(CGF, "calls through member pointers");
+
+ const FunctionProtoType *FPT =
+ MPT->getPointeeType()->getAs<FunctionProtoType>();
+ const CXXRecordDecl *RD =
+ cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl());
+ const llvm::FunctionType *FTy =
+ CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(RD, FPT),
+ FPT->isVariadic());
+ return llvm::Constant::getNullValue(FTy->getPointerTo());
+}
+
+llvm::Value *CGCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF,
+ llvm::Value *Base,
+ llvm::Value *MemPtr,
+ const MemberPointerType *MPT) {
+ ErrorUnsupportedABI(CGF, "loads of member pointers");
+ const llvm::Type *Ty = CGF.ConvertType(MPT->getPointeeType())->getPointerTo();
+ return llvm::Constant::getNullValue(Ty);
+}
+
+llvm::Value *CGCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF,
+ const CastExpr *E,
+ llvm::Value *Src) {
+ ErrorUnsupportedABI(CGF, "member function pointer conversions");
+ return GetBogusMemberPointer(CGM, E->getType());
+}
+
+llvm::Value *
+CGCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF,
+ llvm::Value *L,
+ llvm::Value *R,
+ const MemberPointerType *MPT,
+ bool Inequality) {
+ ErrorUnsupportedABI(CGF, "member function pointer comparison");
+ return CGF.Builder.getFalse();
+}
+
+llvm::Value *
+CGCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
+ llvm::Value *MemPtr,
+ const MemberPointerType *MPT) {
+ ErrorUnsupportedABI(CGF, "member function pointer null testing");
+ return CGF.Builder.getFalse();
+}
+
+llvm::Constant *
+CGCXXABI::EmitMemberPointerConversion(llvm::Constant *C, const CastExpr *E) {
+ return GetBogusMemberPointer(CGM, E->getType());
+}
+
+llvm::Constant *
+CGCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
+ return GetBogusMemberPointer(CGM, QualType(MPT, 0));
+}
+
+llvm::Constant *CGCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) {
+ return GetBogusMemberPointer(CGM,
+ CGM.getContext().getMemberPointerType(MD->getType(),
+ MD->getParent()->getTypeForDecl()));
+}
+
+llvm::Constant *CGCXXABI::EmitMemberPointer(const FieldDecl *FD) {
+ return GetBogusMemberPointer(CGM,
+ CGM.getContext().getMemberPointerType(FD->getType(),
+ FD->getParent()->getTypeForDecl()));
+}
+
+bool CGCXXABI::isZeroInitializable(const MemberPointerType *MPT) {
+ // Fake answer.
+ return true;
+}
+
+void CGCXXABI::BuildThisParam(CodeGenFunction &CGF, FunctionArgList &Params) {
+ const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl());
+
+ // FIXME: I'm not entirely sure I like using a fake decl just for code
+ // generation. Maybe we can come up with a better way?
+ ImplicitParamDecl *ThisDecl
+ = ImplicitParamDecl::Create(CGM.getContext(), 0, MD->getLocation(),
+ &CGM.getContext().Idents.get("this"),
+ MD->getThisType(CGM.getContext()));
+ Params.push_back(std::make_pair(ThisDecl, ThisDecl->getType()));
+ getThisDecl(CGF) = ThisDecl;
+}
+
+void CGCXXABI::EmitThisParam(CodeGenFunction &CGF) {
+ /// Initialize the 'this' slot.
+ assert(getThisDecl(CGF) && "no 'this' variable for function");
+ getThisValue(CGF)
+ = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(getThisDecl(CGF)),
+ "this");
+}
+
+void CGCXXABI::EmitReturnFromThunk(CodeGenFunction &CGF,
+ RValue RV, QualType ResultType) {
+ CGF.EmitReturnOfRValue(RV, ResultType);
+}
+
+CharUnits CGCXXABI::GetArrayCookieSize(QualType ElementType) {
+ return CharUnits::Zero();
+}
+
+llvm::Value *CGCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
+ llvm::Value *NewPtr,
+ llvm::Value *NumElements,
+ QualType ElementType) {
+ // Should never be called.
+ ErrorUnsupportedABI(CGF, "array cookie initialization");
+ return 0;
+}
+
+void CGCXXABI::ReadArrayCookie(CodeGenFunction &CGF, llvm::Value *Ptr,
+ QualType ElementType, llvm::Value *&NumElements,
+ llvm::Value *&AllocPtr, CharUnits &CookieSize) {
+ ErrorUnsupportedABI(CGF, "array cookie reading");
+
+ // This should be enough to avoid assertions.
+ NumElements = 0;
+ AllocPtr = llvm::Constant::getNullValue(CGF.Builder.getInt8PtrTy());
+ CookieSize = CharUnits::Zero();
+}
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